Carthera has enrolled the first 100 participants in its Sonobird critical trial, the largest study to date investigating ultrasound-mediated blood-brain barrier (BBB) opening in patients with recurrent glioblastoma, the company announced yesterday (April 22, 2025).

The France-based medical device firm, a spin-off from Sorbonne University, is developing SonoCloud, an implantable ultrasound-based system intended to temporarily open the BBB and enhance drug delivery to the brain. According to Carthera, nearly all of the 40 planned clinical sites across Europe and the United States are now actively enrolling participants. The company aims to recruit a total of 560 patients by 2026.

The Sonobird study is the world’s first randomized, multicenter, two-arm pivotal trial using ultrasound to open the BBB ahead of chemotherapy in patients with a first recurrence of glioblastoma. It compares standard-of-care regimens, such as lomustine or temozolomide, with carboplatin delivered following BBB opening via SonoCloud.

Dr. Brian Gill, assistant professor of neurosurgery at Columbia University Irving Medical Center, said: “It has been a privilege to offer this trial to patients with recurrent glioblastoma. The underlying concept is highly promising, device implantation has proceeded smoothly and patients have shown strong interest in participating.”

Glioblastoma is an aggressive form of brain cancer with limited treatment options upon recurrence. Carthera claims its technology could improve the delivery and efficacy of chemotherapy agents that traditionally struggle to penetrate the brain’s protective barrier.

“We desperately need new treatments for patients with recurrent glioblastoma,” said Dr. Marjolein Geurts, neuro-oncologist at Erasmus Medical Center in Rotterdam. “SonoCloud has the potential to transform our ability to deliver a high dose of therapeutics to the brain.”

According to the company, more than 550 SonoCloud treatments have already been performed globally, and the device holds both breakthrough and orphan drug designations. Carthera expects the first interim data from the trial to be available shortly.

“Achieving this milestone is an important step in introducing our SonoCloud device to the large patient population urgently in need of solutions to improve treatment outcomes,” said Carthera CEO Frédéric Sottilini.

The trial builds on data from a previous phase 1/2 study (SC9-GBM-01), which showed the feasibility of using SonoCloud to open the BBB and suggested a favorable safety profile for the device when paired with carboplatin monotherapy.